Ariyasāvaka is often found translated as noble disciple.
It is a compound formed with the words ariya and sāvaka. Ariya is said to refer to the generally approved and esteemed customs and ideals of the Aryan clans, covering the racial, social and ethical aspects translated as noble. And sāvaka is translated as disciple.
Noble disciple seems to indicate the disciple as the noble one, but note that in this context for an arahant 'sāvaka' is being used, not ariyasāvaka, which then makes this a little odd; first to regard one as noble and then not. And ironically it makes some wonder who exactly is when noble.
Another rendering is disciple of the noble one(s). At least here people can be disciples without worrying about their status as nobility, but again for the arahant 'sāvakā' is being used, so this too does not fit.
Both translations leave some oddness when trying to assign noble to a certain person. But noble here stood for the social and ethical direction. So it was about the learning/following the good, the highest, righteousness; all of those traits for which aryan stood example. And for this generalization we then get to use 'nobleness'. A monastic is here not a noble one, a virtuous one is here not a noble one, the exalted one is here not a noble one, and the dhamma is here not noble (after all there are unwholesome dhammā) but nobleness is and noble principles are.
So then, disciple of nobleness? But what exactly would that mean? The word disciple implies a certain relationship and since nobleness is an abstract word it leaves this ambiguous. Then let's look at sāvaka as well.
The dictionary says:
Sāvaka [fr. śru] a hearer, disciple.
Hearers have a long standing relation with oral traditions. And here we do not have the problem as with disciple so that fits rather well.
So then for ariyasāvaka we can have 'hearer of nobleness', as in hearer of the good. Even when the exalted ones' words are long gone one can set certain things as higher, nobler. Not to admire but to advance to; thus as to undertake, as practise. Advancing this way keeps siding with the good. And when the dhamma is discovered then it is set as the new highest. So as principle this fits as well.
Now noble is inclined for nobleness; again it is not a person who is noble but rather the nobleness of what is noble. And of what is noble that a hearer gets to be educated about. The ariyasāvaka and arahant are both sāvakā (hearers, hearers of the exalted one's word). Since the arahant is done with going, siding, that direction towards the good, that undertaking, the education, does not apply. This way it can be understood why an arahant is then not referred to as ariyasāvaka.
So we can use either 'hearer of nobleness' or 'hearer of what is noble', both say the same but perhaps the least abstract version makes it more clear. Then a line could go something like this:
'OK here, almsmen, having learned, the hearer of what is noble pays attention ...'
Pāḷi-English
Ariya (adj. — n.) noble.
— sāvaka hearer of what is noble.